I don’t think foreign travel is going to be back for a while, but I think it’s looking likely that beaches will be open mostly as normal in the UK this summer. There will, no doubt, be some social distancing rules in place, but I believe it will happen. Of course, the other question is will the weather be any good?
I’m pretty sure research has revealed that transmission rates were tiny because of visits to the beach. The problems start when people use nearby facilities (queueing, packing into small shops/cafes)